In addition, the P. copri genome encodes
phosphoadenosine phosphosulfate reductase, an oxidoreductase that participates in the production
of thioredoxin. Thioredoxin has been widely implicated in the pathogenesis of RA and significantly
increased concentrations of thioredoxin have been observed in both serum and synovial fluid of RA
patients [42]. (Altså: Bakterien skaper eit stoff som både er implisert i korleis artritt oppstår, og som også finst i ledda hjå RA-pasientar).

Although the direct mechanism has not yet been elucidated, this finding suggests that
the overgrowth of P. copri may have a pathogenic role in the development of NORA. (D. e. nylig oppstått artritt).

It also supports
the hypothesis that normal intestinal microbiota and their degradation products may be involved in
the development of autoimmune arthritis in genetically susceptible individuals, which was previously
proposed by Toivanen in 2003 [43].

Moreover, the gut microbiota also have the capacity to influence
autoimmune disease incidence in genetically predisposed animal models by altering sex-hormone
levels [44].

Another in vivo study demonstrated that the gut microbiota, in association with HLA genes,
determine the innate and adaptive immune system and contribute to the susceptibility to arthritis [45].

Taken together, the underlying mechanistic relationships among gut microbiota, immune system
and RA are under intense investigations. Even though it is still challenging to define the exact role of
gut microbiota in the etiology of RA, current evidence suggests that gut microbiota indeed contribute
to the pathogenesis of RA via multiple potential molecular mechanisms. More mechanistic studies are
needed to elucidate how gut microbiota contribute to the development of RA.

Tuesday, December 6, 2016

Rheumatoid arthritis (RA) is a systemic, inflammatory, and autoimmune disorder.
Gut microbiota play an important role in the etiology of RA. With the considerable progress made in
next-generation sequencing techniques, the identified gut microbiota difference between RA patients
and healthy individuals provides an updated overview of the association between gut microbiota
and RA. We reviewed the reported correlation and underlying molecular mechanisms among gut
microbiota, the immune system, and RA. It has become known that gut microbiota contribute to
the pathogenesis of RA via multiple molecular mechanisms.

The progressive understanding of
the dynamic interaction between gut microbiota and their host will help in establishing a highly
individualized management for each RA patient, and achieve a better efficacy in clinical practice, or
even discovering new drugs for RA.

The second paper, published in Arthritis and Rheumatology, explored another facet of gut bacteria. Dr. Taneja treated one group of arthritis-susceptible mice with a bacterium, Prevotella histicola, and compared that to a group that had no treatment. The study found that mice treated with the bacterium had decreased symptom frequency and severity, and fewer inflammatory conditions associated with rheumatoid arthritis. The treatment produced fewer side effects, such as weight gain and villous atrophy -- a condition that prevents the gut from absorbing nutrients -- that may be linked with other, more traditional treatments.

While human trials have not yet taken place, the mice's immune systems and arthritis mimic humans, and shows promise for similar, positive effects. Since this bacterium is a part of healthy human gut, treatment is less likely to have side effects, says study co-author Joseph Murray, M.D., a Mayo Clinic gastroenterologist.

Jose Scher, MD, a rheumatologist at New York University Langone Medical Center, studies the connection between intestinal bugs and arthritis. He thinks the overgrowth of normally benign bacteria called Prevotella – which are far more abundant in people with untreated RA – may trigger an inflammatory response that targets the joints. It’s also possible Prevotella crowds out beneficial bacteria that keep inflammation in check. Either way, Scher is confident there’s a connection between the microbiome and arthritis.

...

One of the hottest questions right now is whether it will be possible to treat arthritis and other diseases by adjusting the microbiome. A growing number of scientists think so.

Writing in a review article published in the March 2016 issue of Current Opinion in Rheumatology, researchers from the University of Glasgow in the UK noted that “interventions targeting the microbiota may become therapeutically viable for some types of inflammatory arthritis.”

That idea is echoed by Martin Blaser, MD, a microbiologist at New York University Langone Medical Center and a widely respected microbiome expert.

“This is a fertile area for research because we know that particular microbes talk to human physiology in different ways with different vocabularies. As our understanding of this relationship grows, we may use it to regulate disease,” he says.

Monday, December 5, 2016

Recent neurobiological insights into this gut–brain crosstalk have revealed a complex, bidirectional communication system that not only ensures the proper maintenance of gastrointestinal homeostasis and digestion but is likely to have multiple effects on affect, motivation and higher cognitive functions, including intuitive decision making.

Moreover, disturbances of this system have been implicated in a wide range of disorders, including functional and inflammatory gastrointestinal disorders, obesity and eating disorders.

Indeed, emerging data suggest communication between the gut and the brain in anxiety, depression, cognition, and autism spectrum disorder (ASD). The development of a healthy, functional brain depends on key pre- and post-natal events that integrate environmental cues, such as molecular signals from the gut. These cues largely originate from the microbiome, the consortium of symbiotic bacteria that reside within all animals.